https://blog.csdn.net/xxs18326183038/article/details/80622687
在网上找了很多mysql分表的做法，都大同小异，天下文章一大抄，哈哈，今天我也来抄一抄，不过我是经过实战操作的。
参考的是这里 https://www.cnblogs.com/lucky-man/p/6207873.html。我的做法是：
水平分表
1，假设现在是存储用户聊天记录(哈哈，还是抄的上面链接同志的) 预先建了3个表 然后根据用户uid取模来判定将聊天记录存放在哪个表中：
CREATE TABLE `msg_0` ( `id` int(11) NOT NULL AUTO_INCREMENT, `uid` int(11) NOT NULL, `content` varchar(50) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8 CREATE TABLE `msg_1` ( `id` int(11) NOT NULL AUTO_INCREMENT, `uid` int(11) NOT NULL, `content` varchar(50) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8
CREATE TABLE `msg_2` ( `id` int(11) NOT NULL AUTO_INCREMENT, `uid` int(11) NOT NULL, `content` varchar(50) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8 2，php 代码
<?php header("Content-type=text/html;charset=utf8"); $link = mysql_connect("localhost",'root','111111'); if (!$link){ die("数据库连接失败"); } mysql_select_db("test"); //水平分表 $uid = mt_rand(1,100);//模拟用户uid $yu = $uid%3; //分了3个表 所以是%3来取模 $table = "msg_".$yu; //判断是哪个表 $content = "hello word_".$table; //插入数据 $sql="insert into ".$table."(uid,content) values(".$uid.",'".$content."')"; $re = mysql_query($sql); //查询数据 $s = "select * from ".$table; $re = mysql_query($s); while ($row = mysql_fetch_array($re,MYSQL_ASSOC )){ ps($row); } function ps($str){ echo "<pre>"; print_r($str); } function pse($str){ echo "<pre>"; print_r($str); exit; } ?> 就是上面那么多内容，水平分表真的就这么简单么？额，反正在网上找的差不多讲的都是这个意思。还有一种是利用mysql自身的merge引擎分表，跟我这个 差不多，自己查查吧！
垂直分表
垂直分表就是将一个表中不经常用到的，或者像text这种类型比较大的字段挪到一个表中，其他常用的字段单独一个表，
如：现在有个user表：如下，有很多字段，现在分成两个表，一个user1用了存放用户主要的属性字段，另一个表user2，用了存放各种时间相关的字段
[sql] view plain copy <code class="language-sql">mysql> desc user; +----------------+---------------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------------+---------------------+------+-----+---------+----------------+ | id | int(10) unsigned | NO | PRI | NULL | auto_increment | | group_id | int(10) unsigned | NO | | 0 | | | username | varchar(32) | NO | MUL | | | | nickname | varchar(50) | NO | MUL | | | | password | varchar(32) | NO | | | | | salt | varchar(30) | NO | | | | | email | varchar(100) | NO | MUL | | | | mobile | varchar(11) | NO | MUL | | | | avatar | varchar(255) | NO | | | | | birthday | date | NO | | NULL | | | prevtime | int(10) unsigned | NO | | 0 | | | logintime | int(10) unsigned | NO | | 0 | | | loginip | varchar(50) | NO | | | | | loginfailure | tinyint(1) unsigned | NO | | 0 | | | joinip | varchar(50) | NO | | | | | jointime | int(10) unsigned | NO | | 0 | | | createtime | int(10) unsigned | NO | | 0 | | | updatetime | int(10) unsigned | NO | | 0 | | </code>
mysql> desc user1; +----------------+---------------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------------+---------------------+------+-----+---------+----------------+ | id | int(10) unsigned | NO | PRI | NULL | auto_increment | | group_id | int(10) unsigned | NO | | 0 | | | username | varchar(32) | NO | MUL | | | | nickname | varchar(50) | NO | MUL | | | | password | varchar(32) | NO | | | | | salt | varchar(30) | NO | | | | | email | varchar(100) | NO | MUL | | | | mobile | varchar(11) | NO | MUL | | | | avatar | varchar(255) | NO | | | | | birthday | date | NO | | NULL | | mysql> desc user2; +----------------+---------------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------------+---------------------+------+-----+---------+----------------+ | uid | int(10) unsigned | NO | | | | prevtime | int(10) unsigned | NO | | 0 | | | logintime | int(10) unsigned | NO | | 0 | | | loginip | varchar(50) | NO | | | | | loginfailure | tinyint(1) unsigned | NO | | 0 | | | joinip | varchar(50) | NO | | | | | jointime | int(10) unsigned | NO | | 0 | | | createtime | int(10) unsigned | NO | | 0 | | | updatetime | int(10) unsigned | NO | | 0 | | 表user2中通过uid来关联user1表
